Australian transport investigators have announced they have identified a “critical safety issue” with engines fitted to the world’s largest passenger airliner. Some Rolls-Royce Trent 900 engines, which power some Airbus A380 “superjumbos”, may be prone to “fatigue cracking”, which could lead to oil leakage and a fire.

The Australian Transport Safety Bureau (ATSB) said they think this was “central to the engine failure” which occurred on a Qantas A380 on November 4, shortly after take-off from Singapore. The airline grounded all six of its fleet of A380s so they could undergo safety checks before they were put back into service. Late last month, Qantas announced the aircraft were safe and began returning them to service.

A Rolls-Royce engineer testing a Trent 900 engine. Image: US Air Force.

The ATSB said the manufacturing fault with the Trent 900 engines “could lead to an elevated risk of fatigue crack initiation and growth, oil leakage and potential catastrophic engine failure from a resulting oil fire.” The agency urged Rolls-Royce to “address the safety issue and take actions necessary to ensure the safety of flight operations in transport aircraft equipped with Rolls-Royce Trent 900 series engines.”

Qantas emphasised on Thursday that there was “no immediate risk to flight safety,” but said they would conduct further investigations. A statement from the airline said: “Qantas currently has two A380 aircraft in operational service, following the grounding of the fleet on 4 November. Both A380 aircraft will be inspected at the Qantas Jet Base in Sydney. Inspections will commence this afternoon.” Two other airlines use A380 aircraft with Trent engines, Lufthansa and Singapore Airlines; Singapore Airlines said they were checking the engines of their A380s “on a daily basis”. They said: “The new checks advised by the ATSB will be carried out as quickly as possible.”

The incident in Singapore was embarrassing for Airbus. Aviation journalist Tom Ballantyne said the incident in Singapore was “certainly the most serious incident that the A380 has experienced since it entered operations.” The A380 made its first commercial flight in 2007, and is now in service with several other airlines, including Air France and Emirates. It is the largest commercial passenger airliner in the world, with an 840-passenger maximum capacity, though Qantas’ can carry 450.